Site Report: Tesoro - Northstore #9

Site Name:	Tesoro - Northstore #9
Address:	2401 Spenard Road &1104 West Fireweed Lane, Anchorage, AK 99503
File Number:	2100.26.083
Hazard ID:	23720
Status:	Cleanup Complete
Staff:	No Longer Assigned, 9074655229 dec.icunit@alaska.gov
Latitude:	61.198800
Longitude:	-149.905000
Horizontal Datum:	NAD83

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Site Chronology
IC / Closure Details
Documents
Associated Sites

Problems/Comments

During the inspection for needed upgrades of the one 5,000-gallon diesel, and two 10,000-gallon gasoline underground storage tanks, diesel, gasoline, and benzene soil and groundwater contamination was encountered as a result of over filling and/or during filling. Approximately 908.03 tons of contaminated soil was excavated and thermally treated at Alaska Soil Recycling in Anchorage. A soil vapor extraction system was installed, and long-term groundwater monitoring established. The vapor extraction system was ineffective, so and air sparge groundwater treatment system was installed and remains operable. Updated 2-22-07 by Paul Horwath.

Action Information

Action Date	Action	Description	DEC Staff
11/27/1996	Leaking Underground Storage Tank Release Confirmed - Petroleum	LUST Site created in CSP for source area ID 77811 ADD; Gasoline contamination. Dept received letter from RP's consultant advising that sampling done on 10/29/96 showed that the subsurface soils were contaminated around the USTs at this site.	Former Staff
11/27/1996	Site Added to Database		Former Staff
11/5/1997	Update or Other Action	Dept advises RP and consultant by letter that Krieber is now the PM.	Former Staff
11/20/1997	Update or Other Action	ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: TESORO NORTHSTORE	Former Staff
2/17/1998	Leaking Underground Storage Tank Corrective Action Underway	Dept received proposed workplan from consultant for action at this site in 1998.	Former Staff
3/10/1998	Update or Other Action	Dept reviewed workplan and issues letter of approval.	Former Staff
9/11/1998	Update or Other Action	Tanks upgraded with CP rather than closing them. Additional contamination found.	Former Staff
12/16/1998	Underground Storage Tank Site Characterization or Assessment	SA Report received from consultant.	Former Staff
12/16/1998	Leaking Underground Storage Tank Corrective Action Underway	Dept received a CA Workplan for the site.	Former Staff
1/6/1999	Update or Other Action	Dept reviews and responds to SA Report.	Former Staff
2/9/1999	Update or Other Action	Dept approves CA Workplan.	Former Staff
4/12/1999	Leaking Underground Storage Tank Cleanup Initiated - Petroleum	Approval granted by Dept for transport and treatment of contaminated soils from drilling for MWs for the RI that was initiated at this site.	Former Staff
5/5/1999	Release Investigation	RI Report received from the consultant.	Former Staff
6/4/1999	Update or Other Action	Dept reviews and responds to RI Report.	Former Staff
7/21/1999	Leaking Underground Storage Tank Corrective Action Underway	Proposed WP for Phase 2 RI and CAP received by the Dept.	Former Staff
7/22/1999	Update or Other Action	Dept sent ltr, expressing some concerns on the proposed WP.	Former Staff
8/11/1999	Long Term Monitoring Established	Quarterly Monitoring Report received.	Former Staff
8/20/1999	Update or Other Action	Well search report received by the Dept.	Former Staff
9/15/1999	Update or Other Action	Dept reviews and responds to Well Search Report.	Former Staff
9/23/1999	Update or Other Action	Dept reviews and responds to Quarterly Monitoring Report.	Former Staff
11/23/1999	Release Investigation	Installation of three more wells (4,5,6) to detect offsite contamination. GW and soil clean. Reviewed by JBC 4/19/00.	Former Staff
1/25/2000	Update or Other Action	Department reviews and approves of Pilot test - acknowledges that equipment specs are consultant's decision, but general objectives were met.	Former Staff
2/15/2001	Release Investigation	JBC: Install three additional wells to replace MW1-3 that were removed as part of tank removals. Installed three replacement monitoring/SVE wells and initiated treatement at the site. Groundwater to NW, E, and SW offsite is clean. Contamination appears to be at the edge of the property to north and west, but does not likely extend far beneath the roadway.	Former Staff
4/4/2001	Long Term Monitoring Established	February 2001 Monitoring Event report received from Gilfilian Engineering.	Monica English
7/19/2001	Long Term Monitoring Established	May 2001 Monitoring Event report received from Gilfilian Engineering.	Monica English
11/1/2001	Long Term Monitoring Established	August 2001 Monitoring Event report received from Gilfilian Engineering.	Monica English
2/1/2002	Long Term Monitoring Established	November 2001 Monitoring Event report received from Gilfilian Engineering.	Monica English
5/1/2002	Long Term Monitoring Established	Received February 2002 Monitoring Event report from Gilfilian Engineering.	Monica English
9/1/2002	Long Term Monitoring Established	Received May 2002 Monitoring Event report from MWH.	Monica English
2/2/2004	Release Investigation	Approval issued for 2004 Work plan.	Monica English
10/4/2004	Update or Other Action	File number issued 2100.26.083	Aggie Blandford
11/1/2004	Document, Report, or Work plan Review - other	April 2004 Monitoring Event Report. GW contaminant trends consistent with previous sampling. Monitor well MW2 exceeds GCL for benzene, GRO and DRO. The AS remediation system continues to operate.	Monica English
11/15/2004	Update or Other Action	Staff attends annual environmental planning meeting with Tesoro and MWH to discuss workplans for 2005.	Monica English
11/18/2004	Update or Other Action	File number 2100.26.083 assigned and entered into the Fileroom DB and LUST DB.	Alyce Hughey
1/25/2005	Update or Other Action	ADEC issues approval for the 2005 calendar year Corrective Action plan.	Monica English
11/17/2005	Leaking Underground Storage Tank Corrective Action Underway	Monica English sent an approval letter for the Corrective Action Work Plan for 2006.	Alyce Hughey
10/9/2006	Update or Other Action	Project manager changed from Monica English to Paul Horwath, per Paul Horwath.	Alyce Hughey
11/29/2006	Update or Other Action	Using Figure 1 from the December 2002 Monitoring Event, Air Sparge Well Installation and SVE Pilot Study Report, from Montgomery Watson Harza, dated February 2003, in conjunction with TopoZone Pro and the Recorders Office, and Anchorage Live, entered the coordinates for this site. Metadata includes No Topo Basemap, Black and White Aerial Photo, TopoZone Pro Street Maps, on a Medium Size Map, View Scale 1:9,840, Coordinate Datum NAD83. High degree of confidence in accuracy of location.	Alyce Hughey
2/22/2007	Document, Report, or Work plan Review - other	Reviewed MWH's Tesoro 2 Go Mart #9, October 2006 Monitoring Event Report Final, dated December 2006. Air sparge treatment continues to be operated at this site, and GW remains contaminated with DRO, GRO, benzene, and ethylbenzene. GW contaminate concentrations increased from the prior sampling event, but all in all are considered stable, and have diminished since air sparge treatment began in the fall of 2002.	Paul Horwath
4/9/2007	Leaking Underground Storage Tank Corrective Action Underway	Approved MWH's Work Plan for Confirmation Soil Borings, Tesoro 2 Go Mart #9, dated February 16, 2007. Eight soil borings and one new GW monitoring wells will be installed at this site in 2007.	Paul Horwath
4/10/2007	Exposure Tracking Model Ranking	Initial ETM ranking completed.	Paul Horwath
9/27/2007	Update or Other Action	ADEC authorized the transport of 55 gallons of petroleum contaminated soil from this site to ASR in Anchorage. Post-treatment analyses required of ASR include BTEX, GRO, and DRO.	Paul Horwath
10/31/2007	Update or Other Action	Provide a written response to ASR's request for a closure letter for contaminated soils received from this site.	Paul Horwath
12/20/2007	Document, Report, or Work plan Review - other	Reviewed the April 2007 Monitoring Event Report prepared by MWH, dated July 2007. GW contamination levels have decreased since treatment began in 2002, however levels have remained steady for the past several years, and still exceed ADEC GW cleanup levels. Air sparge groundwater treatment occuring at this time. An additional MW is to be installed down-gradient of the residual GW contamination.	Paul Horwath
4/17/2008	Document, Report, or Work plan Review - other	Reviewed the October 2007 Monitoring Event Report Final prepared by MWH, dated February 2008. GW contamination levels have decreased since treatment began in 2002, however levels have remained steady for the past several years in MW-2, and still exceed ADEC GW cleanup levels. Air sparge groundwater treatment continues at this time. An additional MW is to be installed down-gradient of the known residual GW contamination in order to establish the downgradient extent of contamination.	Paul Horwath
9/17/2008	Document, Report, or Work plan Review - other	Reviewed the August 2007 Confirmation Soil Borings Report, from MWH, dated June 2008 for Paul Horwath and provided him a review of the report for his review. Petroleum soil contamination was encountered that exceeds the soil cleanup levels for Benzene, Toluene, Ethylbenzene, Xylenes, GRO, and DRO. A work plan needs to be preparted to address the remaining contamination issues for the site.	Alyce Hughey
9/18/2008	Document, Report, or Work plan Review - other	Reviewed the April 2008 Monitoring Event Report, from MWH, dated July 2008 for Paul Horwath and provided him a summary of the report for his review. Groundwater concentrations in MW-2 remain steady at a level just above the groundwater cleanup levels, where the concentrations in MW-3 have decreased to a level below the groundwater cleanup levels for two consecutive quarters.	Alyce Hughey
9/25/2008	Document, Report, or Work plan Review - other	Review MWH's April 2008 Monitoring Event Report, dated July 2008. Identify issues with lab data validation by MWH. Contact MWH to obtain corrections to the ADEC Lab Data Review Checklist, and groundwater flow direction and gradient did not correspond to the elevations listed in the body of the report and within Figure 2.	Paul Horwath
10/22/2008	Document, Report, or Work plan Review - other	Reviewed and discussed with Paul Horwath MWH's April 2008 Monitoring Event Report (Revised), dated October 2008. Issues with the lab data valadation were addressed, and erroneous elevation values were used to create the original plot. The corrected values were plotted and the amended GW direction and gradient were inserted into the report.	Alyce Hughey
12/17/2008	Update or Other Action	Reviewed the October 2008 Monitoring Event Report, dated November 2008, from MWH for Paul Horwath and provided him with a summary of the report for his review and oversight. Site conditions continue to improve with groundwater concentrations in MW-2 continuing to decrease with only DRO remaining above the groundwater cleanup level; were the concentrations in MW-3 have remained undetected for all the analytes for three consecutive monitoring events.	Alyce Hughey
2/26/2009	Document, Report, or Work plan Review - other	Reviewed the November 2008 Monitoring Well Installation and Monitoring Event report, dated December 2008, from MWH for Paul Horwath and provided him a summary for his review and oversight. During the installation of an additional monitoring well to the north of the site, MW-7, Benzene was detected above the soil cleanup levels at a depth of 18 feet below ground surface, which is where groundwater was encountered. Toluene, Ethylbenzene, Xylenes and GRO was detected in the soil at a depth of 18 feet below ground surface but remained below the soil cleanup levels. The groundwater sample taken from the new monitoring well, MW-7 detected Benzene and Xylenes that were below the groundwater cleanup levels. The results of the monitoring well installation, indicates that off-site migration of Benzene contamination has occurred at this site.	Alyce Hughey
4/14/2009	Document, Report, or Work plan Review - other	Reviewed the January 2009 Monitoring Event Report, dated March 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. The contaminant concentrations in MW-2, which is located north and down gradient of the former underground storage tanks have been oscillating near the groundwater cleanup levels since 2003, and MW-3 has remained below the groundwater cleanup levels since 2005. Only minor traces of contamination are being detected in the new monitoring well installed off site during the month of November of 2008. A work plan outlining additional remediation actions will be submitted to ADEC during 2009 in order to better address the remaining contamination at the site.	Alyce Hughey
8/24/2009	Document, Report, or Work plan Review - other	Reviewed and approved the Supplemental Work Plan for Chemical Oxidation Treatment, dated August 14, 2009 for the Tesoro Northstore #9, from MWH.	Paul Horwath
11/24/2009	Document, Report, or Work plan Review - other	Reviewed the July 2009 Monitoring Event Report, dated September 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. The July 2009 groundwater monitoring event indicated an increase in Benzene, GRO and DRO groundwater concentrations in MW-2. MW-3 remains undetected for all the analytes tested for. In order to address the remaining contamination MWH has started chemical oxidation treatments using Potassium Permanganate by injecting it into the subsurface within the zone of contamination via several direct-push wells. Data presented at the annual ADEC/Tesoro meeting indicated that the groundwater concentrations are reducing in the monitoring wells. During the second round of injections soil samples will be taken, and at least 50% higher amount of Potassium Permanganate will be injected into the subsurface via several direct-push wells within the area of the remaining contamination.	Alyce Hughey
7/16/2010	Document, Report, or Work plan Review - other	Reviewed the March 2010 Monitoring Event Report, dated May 2010, from MWH for Paul Horwath. The March of 2010 groundwater sampling indicates that the GRO concentrations are decreasing within MW-2. The use of potassium permanganate as a chemical oxidation treatment appears to be effective in decreasing the concentrations within the groundwater at the site. Future groundwater monitoring, and the installation of confirmation soil boring samples will confirm the effectiveness of the potassium permanganate treatments performed at the site.	Alyce Hughey
11/16/2010	Meeting or Teleconference Held	Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2011.	Alyce Hughey
11/16/2010	Meeting or Teleconference Held	Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2011.	Paul Horwath
2/1/2011	Document, Report, or Work plan Review - other	Reviewed the October 2010 Monitoring Event Report, dated December 2010, from MWH. The October 2010 groundwater sampling indicates that the GRO and DRO concentrations in MW-2 are above the groundwater cleanup levels, with a decrease in GRO concentrations from March to October of 2010. MW-3 detected GRO at 0.0515 mg/L and all the other analytes were not detected in the samples taken. The remediation activities conducted in 2010 included chemical oxidation to address the remaining soil and groundwater impacts, and confirmation soil borings. A report will be submitted in the future discussing the potassium permanganate treatments and the results of the confirmation soil borings taken.	Alyce Hughey
3/17/2011	Document, Report, or Work plan Review - other	Reviewed and approved the March 16, 2011 Field Scale Pilot Study for Chemical Oxidation Treatment Corrective Action Plan, from MWH. The corrective action plan includes the application of Sodium Persulfate for In-Situ Chemical Oxidation for treatment of the petroleum contaminated soil and groundwater.	Paul Horwath
4/27/2011	Document, Report, or Work plan Review - other	Reviewed the 2010 Chemical Oxidation and Soil Boring Report, dated March 2011, from MWH. The findings of the field parameters after the October 2009 potassium permanganate injection were a notable decrease in pH and an increase in oxidation reduction. The field parameters could not be verified after the April 2010 injection due to the erratic readings and difficulty calibrating the field instrument. The groundwater concentrations showed an increase in GRO and DRO in MW-2 after the first round of injections with a continual increase after the second round of injections, also, with an increase in DRO concentrations seen in MW-3 after the second round of injections. It is thought that the increase in concentrations is caused by the contact of the potassium permanganate with the contaminants thereby mobilizing the contaminants. The findings of the soil boring concentrations showed that some areas of previous contamination have significantly decreased SB-2, SB-3, SB-4, and SB-8 while others have not changed SB-5, SB-6, and SB-7.	Alyce Hughey
6/22/2011	Document, Report, or Work plan Review - other	Reviewed the February 2011 Monitoring Event Report, dated May 2011, from MWH. The February 2011 groundwater sampling indicated that Benzene, Ethylbenzene, GRO and DRO groundwater contamination still remains in MW-2. These concentrations are similar with results of the July of 2009 sampling. It is thought that the variable concentrations might be attributed to contaminant desorption resulting from the ongoing chemical oxidation injections performed at the site. Monitoring well MW-3 tested undetected for all analytes. It was noted during the February monitoring event that most of the monitoring wells had heaved during the winter and it is planned for the wells to be cut down and resurveyed during the second quarter of 2011.	Alyce Hughey
10/7/2011	Document, Report, or Work plan Review - other	Reviewed the August 2011 Monitoring Event Report, dated September 2011, from MWH. The August 2011 groundwater sampling showed a decrease in concentrations within MW-2, with DRO the only analyte testing above the groundwater cleanup levels at 2.39 mg/L. Monitoring well MW-3 tested undetected for all analytes other than DRO at a concentration of 0.509 mg/L.	Alyce Hughey
10/19/2011	Update or Other Action	Reviewed the additional information received regarding the integrity of the monitoring wells due to heaving during the winter months as was noted in the February Monitoring Event report. MW-2 was cut down about 1.75", and all the rest of the wells were in good condition. The wells were surveyed in and the groundwater flow and gradient was calculated. Groundwater was flowing with a northwesterly flow direction at 341 degrees, and gradient of 0.0013, which is consistent with previous events.	Alyce Hughey
12/1/2011	Meeting or Teleconference Held	Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012.	Alyce Hughey
12/1/2011	Meeting or Teleconference Held	Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012.	Paul Horwath
1/5/2012	Document, Report, or Work plan Review - other	Reviewed the 2011 Chemical Oxidation Pilot Study Report, dated November 2011, from MWH. On June 11, 2011 the in-situ chemical oxidation was performed using Sodium Persulfate in two subsurface injection points in the area of the residual soil contamination. The injections were advanced to 18 feet below ground surface, with 275-gallons of 12 percent Sodium Persulfate solution and activated with 140-gallons of 8 percent hydrogen peroxide. Monitoring well MW-2 was used to conduct field measurements one day prior; two, nine, sixteen, twenty-four and sixty-eight days after, the injection. The biggest difference was observed two days after the injection, with measurements returning to pre injection parameters within a week or so after the injection. Laboratory intrinsic parameters were conducted for Sodium and Total Organic Carbon. The biggest difference was observed two days after the injection with sodium at 395,000 ug/l and total organic carbon at 18.8 mg/L. These levels returned to approximately pre-injection levels within a couple of weeks after the injection. The results of the groundwater sampling conducted sixty-eight days after the injection showed an increase in all analytes with DRO being detected above the groundwater cleanup levels in MW-2. It is believed that the increase may be caused by a reaction of the chemical oxidant with the contaminants, thereby possibly mobilizing the contaminants. Two soil borings were advanced in the area of the injections with soil sample results detecting Ethylbenzene at 19.6 mg/kg, Xylenes at 107 mg/kg, GRO at 1,560 mg/kg, and DRO at 368 mg/kg at twenty feet below ground surface.	Alyce Hughey
2/16/2012	Exposure Tracking Model Ranking	A new updated ranking with ETM has been completed for source area 77811 Former USTs.	Alyce Hughey
4/10/2012	Document, Report, or Work plan Review - other	Reviewed the February 2012 Monitoring Event Report, dated April 2012, from MWH. During the February 24, 2012 groundwater sampling event, all site monitoring wells, MW-1 through MW-7, and the drinking water well located cross-gradient from the site at OK Beauty Salon were sampled. DRO was detected at 2.37 mg/L above the groundwater cleanup levels in MW-2, and DRO was detected at concentrations below the groundwater cleanup levels in MW-1, MW-3, MW-4, and MW-6. Benzene, Toluene, Ethylbenzene, Xylenes and GRO were detected at concentrations below the groundwater cleanup levels in MW-2. The drinking water well at OK Beauty Salon did not detect any analytes in the drinking water sample collected on October 11, 2011.	Alyce Hughey
4/27/2012	Exposure Tracking Model Ranking	A new updated ranking with ETM has been completed for source area 77811 Former USTs.	Paul Horwath
4/27/2012	Exposure Tracking Model Ranking	Initial ranking with ETM completed for source area id: 77811 name: Former USTs	Paul Horwath
5/3/2012	Cleanup Complete Determination Issued	Following the completion of remedial action performed at this site from 1996 to 2011, residual soil contamination remains in the subsurface soil exceeding the ADEC’s Method Two ‘Migration to Groundwater’ soil cleanup levels in the area along the northern and western property boundaries along West Fireweed Land and Spenard Road. Residual groundwater contamination remains on site exceeding the ADEC’s Table C Groundwater Cleanup Levels. The affected groundwater is not currently used as a drinking water source, and the site is serviced by the City of Anchorage public water and sewer systems. The most current soil sample analytical data reported BTEX, GRO, and DRO contamination exceeding the applicable soil cleanup levels, along the northern and western property boundary, along West Fireweed Lane and Spenard Road. Any proposal to excavate, transport, move, treat, and/or dispose of residual contaminated soil at this “site” requires prior ADEC approval. Municipal public water service is currently provided to this property. Water wells may not be installed on this property without the prior notification, and approval, of ADEC. All groundwater monitoring wells, treatment wells, and subsurface treatment piping associated with this project must be properly decommissioned in accordance with ADEC’s November 2011 Monitoring Well Guidance. Decommissioning work should be completed when frost is not present in the soil. The decommissioning of these wells and any subsurface treatment piping should occur before August 30, 2012, and must be documented in a written report submitted to ADEC by November 30, 2012.	Paul Horwath
5/3/2012	Long Term Monitoring Complete	Administrative action on 5/1/2013.	Kristin Thompson
6/6/2012	Meeting or Teleconference Held	Staff attended the mid-year planning meeting at the ADEC office in Soldotna to discuss the decommissioning of monitoring wells and the recording of the Notice of Environmental Contamination for the site.	Alyce Hughey
7/17/2012	Document, Report, or Work plan Review - other	Reviewed the Decommissioning Work Plan for 2012, dated July 12, 2012, prepared by MWH, and issued a conditional approval to decommission MW-4, MW-5, MW-6, MW-7, SVE/MW-1, SVE/MW-2, SVE/MW-3 and AS-1. Conditions include 1) Our understanding and interpretation of this work plan is that a bentonite grout slurry will be used to fill the voids left during removal of the MW casings, and to pressure grout any piping associated with SVE/AS wells and subsurface delivery piping to be left in the subsurface. The use of bentonite chips or non-grout should only be substituted with our prior approval. There are drilling contractors preferring to use dry bentonite chips or pellets, but the drilling contractor shall not be allowed to take control of this field work and substitute dry/solid bentonite chips or pellets without prior ADEC approval. 2) Following the completion of this work, a written report documenting the implementation and completion of these approved work tasks shall be prepared and provided to our office, complete with the signature of the “qualified person” responsible for observing and documenting the field work.	Paul Horwath
11/14/2012	Meeting or Teleconference Held	Paul Horwath and Alyce Hughey attended annual planning meeting at MWH office in Anchorage to discuss the decommissioning activities conducted at the site in 2012.	Alyce Hughey
1/2/2013	Document, Report, or Work plan Review - other	Reviewed the August 2012 Monitoring Wells/Remediation System Decommissioning Report, dated November 6, 2012, from MWH. On August 22, 2012 four groundwater monitoring wells (MW-4, MW-5, MW-6 and MW-7), one air sparge well (AS-1), and three combination soil vapor extraction/monitoring wells (SVE/MW-1, SVE/MW-2 and SVE/MW-3) were decommissioned in accordance to the approved July 12, 2012 Decommissioning Work Plan for 2012 Former Tesoro 2 Go Mart #9 and ADEC’s July 17, 2012 e-mail correspondence with conditions.	Alyce Hughey

Action Date

Action

Description

DEC Staff

11/27/1996

Leaking Underground Storage Tank Release Confirmed - Petroleum

LUST Site created in CSP for source area ID 77811 ADD; Gasoline contamination. Dept received letter from RP's consultant advising that sampling done on 10/29/96 showed that the subsurface soils were contaminated around the USTs at this site.

Former Staff

11/27/1996

Site Added to Database

Former Staff

11/5/1997

Update or Other Action

Dept advises RP and consultant by letter that Krieber is now the PM.

Former Staff

11/20/1997

Update or Other Action

ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: TESORO NORTHSTORE

Former Staff

2/17/1998

Leaking Underground Storage Tank Corrective Action Underway

Dept received proposed workplan from consultant for action at this site in 1998.

Former Staff

3/10/1998

Update or Other Action

Dept reviewed workplan and issues letter of approval.

Former Staff

9/11/1998

Update or Other Action

Tanks upgraded with CP rather than closing them. Additional contamination found.

Former Staff

12/16/1998

Underground Storage Tank Site Characterization or Assessment

SA Report received from consultant.

Former Staff

12/16/1998

Leaking Underground Storage Tank Corrective Action Underway

Dept received a CA Workplan for the site.

Former Staff

1/6/1999

Update or Other Action

Dept reviews and responds to SA Report.

Former Staff

2/9/1999

Update or Other Action

Dept approves CA Workplan.

Former Staff

4/12/1999

Leaking Underground Storage Tank Cleanup Initiated - Petroleum

Approval granted by Dept for transport and treatment of contaminated soils from drilling for MWs for the RI that was initiated at this site.

Former Staff

5/5/1999

Release Investigation

RI Report received from the consultant.

Former Staff

6/4/1999

Update or Other Action

Dept reviews and responds to RI Report.

Former Staff

7/21/1999

Leaking Underground Storage Tank Corrective Action Underway

Proposed WP for Phase 2 RI and CAP received by the Dept.

Former Staff

7/22/1999

Update or Other Action

Dept sent ltr, expressing some concerns on the proposed WP.

Former Staff

8/11/1999

Long Term Monitoring Established

Quarterly Monitoring Report received.

Former Staff

8/20/1999

Update or Other Action

Well search report received by the Dept.

Former Staff

9/15/1999

Update or Other Action

Dept reviews and responds to Well Search Report.

Former Staff

9/23/1999

Update or Other Action

Dept reviews and responds to Quarterly Monitoring Report.

Former Staff

11/23/1999

Release Investigation

Installation of three more wells (4,5,6) to detect offsite contamination. GW and soil clean. Reviewed by JBC 4/19/00.

Former Staff

1/25/2000

Update or Other Action

Department reviews and approves of Pilot test - acknowledges that equipment specs are consultant's decision, but general objectives were met.

Former Staff

2/15/2001

Release Investigation

JBC: Install three additional wells to replace MW1-3 that were removed as part of tank removals. Installed three replacement monitoring/SVE wells and initiated treatement at the site. Groundwater to NW, E, and SW offsite is clean. Contamination appears to be at the edge of the property to north and west, but does not likely extend far beneath the roadway.

Former Staff

4/4/2001

Long Term Monitoring Established

February 2001 Monitoring Event report received from Gilfilian Engineering.

Monica English

7/19/2001

Long Term Monitoring Established

May 2001 Monitoring Event report received from Gilfilian Engineering.

Monica English

11/1/2001

Long Term Monitoring Established

August 2001 Monitoring Event report received from Gilfilian Engineering.

Monica English

2/1/2002

Long Term Monitoring Established

November 2001 Monitoring Event report received from Gilfilian Engineering.

Monica English

5/1/2002

Long Term Monitoring Established

Received February 2002 Monitoring Event report from Gilfilian Engineering.

Monica English

9/1/2002

Long Term Monitoring Established

Received May 2002 Monitoring Event report from MWH.

Monica English

2/2/2004

Release Investigation

Approval issued for 2004 Work plan.

Monica English

10/4/2004

Update or Other Action

File number issued 2100.26.083

Aggie Blandford

11/1/2004

Document, Report, or Work plan Review - other

April 2004 Monitoring Event Report. GW contaminant trends consistent with previous sampling. Monitor well MW2 exceeds GCL for benzene, GRO and DRO. The AS remediation system continues to operate.

Monica English

11/15/2004

Update or Other Action

Staff attends annual environmental planning meeting with Tesoro and MWH to discuss workplans for 2005.

Monica English

11/18/2004

Update or Other Action

File number 2100.26.083 assigned and entered into the Fileroom DB and LUST DB.

Alyce Hughey

1/25/2005

Update or Other Action

ADEC issues approval for the 2005 calendar year Corrective Action plan.

Monica English

11/17/2005

Leaking Underground Storage Tank Corrective Action Underway

Monica English sent an approval letter for the Corrective Action Work Plan for 2006.

Alyce Hughey

10/9/2006

Update or Other Action

Project manager changed from Monica English to Paul Horwath, per Paul Horwath.

Alyce Hughey

11/29/2006

Update or Other Action

Using Figure 1 from the December 2002 Monitoring Event, Air Sparge Well Installation and SVE Pilot Study Report, from Montgomery Watson Harza, dated February 2003, in conjunction with TopoZone Pro and the Recorders Office, and Anchorage Live, entered the coordinates for this site. Metadata includes No Topo Basemap, Black and White Aerial Photo, TopoZone Pro Street Maps, on a Medium Size Map, View Scale 1:9,840, Coordinate Datum NAD83. High degree of confidence in accuracy of location.

Alyce Hughey

2/22/2007

Document, Report, or Work plan Review - other

Reviewed MWH's Tesoro 2 Go Mart #9, October 2006 Monitoring Event Report Final, dated December 2006. Air sparge treatment continues to be operated at this site, and GW remains contaminated with DRO, GRO, benzene, and ethylbenzene. GW contaminate concentrations increased from the prior sampling event, but all in all are considered stable, and have diminished since air sparge treatment began in the fall of 2002.

Paul Horwath

4/9/2007

Leaking Underground Storage Tank Corrective Action Underway

Approved MWH's Work Plan for Confirmation Soil Borings, Tesoro 2 Go Mart #9, dated February 16, 2007. Eight soil borings and one new GW monitoring wells will be installed at this site in 2007.

Paul Horwath

4/10/2007

Exposure Tracking Model Ranking

Initial ETM ranking completed.

Paul Horwath

9/27/2007

Update or Other Action

ADEC authorized the transport of 55 gallons of petroleum contaminated soil from this site to ASR in Anchorage. Post-treatment analyses required of ASR include BTEX, GRO, and DRO.

Paul Horwath

10/31/2007

Update or Other Action

Provide a written response to ASR's request for a closure letter for contaminated soils received from this site.

Paul Horwath

12/20/2007

Document, Report, or Work plan Review - other

Reviewed the April 2007 Monitoring Event Report prepared by MWH, dated July 2007. GW contamination levels have decreased since treatment began in 2002, however levels have remained steady for the past several years, and still exceed ADEC GW cleanup levels. Air sparge groundwater treatment occuring at this time. An additional MW is to be installed down-gradient of the residual GW contamination.

Paul Horwath

4/17/2008

Document, Report, or Work plan Review - other

Reviewed the October 2007 Monitoring Event Report Final prepared by MWH, dated February 2008. GW contamination levels have decreased since treatment began in 2002, however levels have remained steady for the past several years in MW-2, and still exceed ADEC GW cleanup levels. Air sparge groundwater treatment continues at this time. An additional MW is to be installed down-gradient of the known residual GW contamination in order to establish the downgradient extent of contamination.

Paul Horwath

9/17/2008

Document, Report, or Work plan Review - other

Reviewed the August 2007 Confirmation Soil Borings Report, from MWH, dated June 2008 for Paul Horwath and provided him a review of the report for his review. Petroleum soil contamination was encountered that exceeds the soil cleanup levels for Benzene, Toluene, Ethylbenzene, Xylenes, GRO, and DRO. A work plan needs to be preparted to address the remaining contamination issues for the site.

Alyce Hughey

9/18/2008

Document, Report, or Work plan Review - other

Reviewed the April 2008 Monitoring Event Report, from MWH, dated July 2008 for Paul Horwath and provided him a summary of the report for his review. Groundwater concentrations in MW-2 remain steady at a level just above the groundwater cleanup levels, where the concentrations in MW-3 have decreased to a level below the groundwater cleanup levels for two consecutive quarters.

Alyce Hughey

9/25/2008

Document, Report, or Work plan Review - other

Review MWH's April 2008 Monitoring Event Report, dated July 2008. Identify issues with lab data validation by MWH. Contact MWH to obtain corrections to the ADEC Lab Data Review Checklist, and groundwater flow direction and gradient did not correspond to the elevations listed in the body of the report and within Figure 2.

Paul Horwath

10/22/2008

Document, Report, or Work plan Review - other

Reviewed and discussed with Paul Horwath MWH's April 2008 Monitoring Event Report (Revised), dated October 2008. Issues with the lab data valadation were addressed, and erroneous elevation values were used to create the original plot. The corrected values were plotted and the amended GW direction and gradient were inserted into the report.

Alyce Hughey

12/17/2008

Update or Other Action

Reviewed the October 2008 Monitoring Event Report, dated November 2008, from MWH for Paul Horwath and provided him with a summary of the report for his review and oversight. Site conditions continue to improve with groundwater concentrations in MW-2 continuing to decrease with only DRO remaining above the groundwater cleanup level; were the concentrations in MW-3 have remained undetected for all the analytes for three consecutive monitoring events.

Alyce Hughey

2/26/2009

Document, Report, or Work plan Review - other

Reviewed the November 2008 Monitoring Well Installation and Monitoring Event report, dated December 2008, from MWH for Paul Horwath and provided him a summary for his review and oversight. During the installation of an additional monitoring well to the north of the site, MW-7, Benzene was detected above the soil cleanup levels at a depth of 18 feet below ground surface, which is where groundwater was encountered. Toluene, Ethylbenzene, Xylenes and GRO was detected in the soil at a depth of 18 feet below ground surface but remained below the soil cleanup levels. The groundwater sample taken from the new monitoring well, MW-7 detected Benzene and Xylenes that were below the groundwater cleanup levels. The results of the monitoring well installation, indicates that off-site migration of Benzene contamination has occurred at this site.

Alyce Hughey

4/14/2009

Document, Report, or Work plan Review - other

Reviewed the January 2009 Monitoring Event Report, dated March 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. The contaminant concentrations in MW-2, which is located north and down gradient of the former underground storage tanks have been oscillating near the groundwater cleanup levels since 2003, and MW-3 has remained below the groundwater cleanup levels since 2005. Only minor traces of contamination are being detected in the new monitoring well installed off site during the month of November of 2008. A work plan outlining additional remediation actions will be submitted to ADEC during 2009 in order to better address the remaining contamination at the site.

Alyce Hughey

8/24/2009

Document, Report, or Work plan Review - other

Reviewed and approved the Supplemental Work Plan for Chemical Oxidation Treatment, dated August 14, 2009 for the Tesoro Northstore #9, from MWH.

Paul Horwath

11/24/2009

Document, Report, or Work plan Review - other

Reviewed the July 2009 Monitoring Event Report, dated September 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. The July 2009 groundwater monitoring event indicated an increase in Benzene, GRO and DRO groundwater concentrations in MW-2. MW-3 remains undetected for all the analytes tested for. In order to address the remaining contamination MWH has started chemical oxidation treatments using Potassium Permanganate by injecting it into the subsurface within the zone of contamination via several direct-push wells. Data presented at the annual ADEC/Tesoro meeting indicated that the groundwater concentrations are reducing in the monitoring wells. During the second round of injections soil samples will be taken, and at least 50% higher amount of Potassium Permanganate will be injected into the subsurface via several direct-push wells within the area of the remaining contamination.

Alyce Hughey

7/16/2010

Document, Report, or Work plan Review - other

Reviewed the March 2010 Monitoring Event Report, dated May 2010, from MWH for Paul Horwath. The March of 2010 groundwater sampling indicates that the GRO concentrations are decreasing within MW-2. The use of potassium permanganate as a chemical oxidation treatment appears to be effective in decreasing the concentrations within the groundwater at the site. Future groundwater monitoring, and the installation of confirmation soil boring samples will confirm the effectiveness of the potassium permanganate treatments performed at the site.

Alyce Hughey

11/16/2010

Meeting or Teleconference Held

Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2011.

Alyce Hughey

11/16/2010

Meeting or Teleconference Held

Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2011.

Paul Horwath

2/1/2011

Document, Report, or Work plan Review - other

Reviewed the October 2010 Monitoring Event Report, dated December 2010, from MWH. The October 2010 groundwater sampling indicates that the GRO and DRO concentrations in MW-2 are above the groundwater cleanup levels, with a decrease in GRO concentrations from March to October of 2010. MW-3 detected GRO at 0.0515 mg/L and all the other analytes were not detected in the samples taken. The remediation activities conducted in 2010 included chemical oxidation to address the remaining soil and groundwater impacts, and confirmation soil borings. A report will be submitted in the future discussing the potassium permanganate treatments and the results of the confirmation soil borings taken.

Alyce Hughey

3/17/2011

Document, Report, or Work plan Review - other

Reviewed and approved the March 16, 2011 Field Scale Pilot Study for Chemical Oxidation Treatment Corrective Action Plan, from MWH. The corrective action plan includes the application of Sodium Persulfate for In-Situ Chemical Oxidation for treatment of the petroleum contaminated soil and groundwater.

Paul Horwath

4/27/2011

Document, Report, or Work plan Review - other

Reviewed the 2010 Chemical Oxidation and Soil Boring Report, dated March 2011, from MWH. The findings of the field parameters after the October 2009 potassium permanganate injection were a notable decrease in pH and an increase in oxidation reduction. The field parameters could not be verified after the April 2010 injection due to the erratic readings and difficulty calibrating the field instrument. The groundwater concentrations showed an increase in GRO and DRO in MW-2 after the first round of injections with a continual increase after the second round of injections, also, with an increase in DRO concentrations seen in MW-3 after the second round of injections. It is thought that the increase in concentrations is caused by the contact of the potassium permanganate with the contaminants thereby mobilizing the contaminants. The findings of the soil boring concentrations showed that some areas of previous contamination have significantly decreased SB-2, SB-3, SB-4, and SB-8 while others have not changed SB-5, SB-6, and SB-7.

Alyce Hughey

6/22/2011

Document, Report, or Work plan Review - other

Reviewed the February 2011 Monitoring Event Report, dated May 2011, from MWH. The February 2011 groundwater sampling indicated that Benzene, Ethylbenzene, GRO and DRO groundwater contamination still remains in MW-2. These concentrations are similar with results of the July of 2009 sampling. It is thought that the variable concentrations might be attributed to contaminant desorption resulting from the ongoing chemical oxidation injections performed at the site. Monitoring well MW-3 tested undetected for all analytes. It was noted during the February monitoring event that most of the monitoring wells had heaved during the winter and it is planned for the wells to be cut down and resurveyed during the second quarter of 2011.

Alyce Hughey

10/7/2011

Document, Report, or Work plan Review - other

Reviewed the August 2011 Monitoring Event Report, dated September 2011, from MWH. The August 2011 groundwater sampling showed a decrease in concentrations within MW-2, with DRO the only analyte testing above the groundwater cleanup levels at 2.39 mg/L. Monitoring well MW-3 tested undetected for all analytes other than DRO at a concentration of 0.509 mg/L.

Alyce Hughey

10/19/2011

Update or Other Action

Reviewed the additional information received regarding the integrity of the monitoring wells due to heaving during the winter months as was noted in the February Monitoring Event report. MW-2 was cut down about 1.75", and all the rest of the wells were in good condition. The wells were surveyed in and the groundwater flow and gradient was calculated. Groundwater was flowing with a northwesterly flow direction at 341 degrees, and gradient of 0.0013, which is consistent with previous events.

Alyce Hughey

12/1/2011

Meeting or Teleconference Held

Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012.

Alyce Hughey

12/1/2011

Meeting or Teleconference Held

Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012.

Paul Horwath

1/5/2012

Document, Report, or Work plan Review - other

Reviewed the 2011 Chemical Oxidation Pilot Study Report, dated November 2011, from MWH. On June 11, 2011 the in-situ chemical oxidation was performed using Sodium Persulfate in two subsurface injection points in the area of the residual soil contamination. The injections were advanced to 18 feet below ground surface, with 275-gallons of 12 percent Sodium Persulfate solution and activated with 140-gallons of 8 percent hydrogen peroxide. Monitoring well MW-2 was used to conduct field measurements one day prior; two, nine, sixteen, twenty-four and sixty-eight days after, the injection. The biggest difference was observed two days after the injection, with measurements returning to pre injection parameters within a week or so after the injection. Laboratory intrinsic parameters were conducted for Sodium and Total Organic Carbon. The biggest difference was observed two days after the injection with sodium at 395,000 ug/l and total organic carbon at 18.8 mg/L. These levels returned to approximately pre-injection levels within a couple of weeks after the injection. The results of the groundwater sampling conducted sixty-eight days after the injection showed an increase in all analytes with DRO being detected above the groundwater cleanup levels in MW-2. It is believed that the increase may be caused by a reaction of the chemical oxidant with the contaminants, thereby possibly mobilizing the contaminants. Two soil borings were advanced in the area of the injections with soil sample results detecting Ethylbenzene at 19.6 mg/kg, Xylenes at 107 mg/kg, GRO at 1,560 mg/kg, and DRO at 368 mg/kg at twenty feet below ground surface.

Alyce Hughey

2/16/2012

Exposure Tracking Model Ranking

A new updated ranking with ETM has been completed for source area 77811 Former USTs.

Alyce Hughey

4/10/2012

Document, Report, or Work plan Review - other

Reviewed the February 2012 Monitoring Event Report, dated April 2012, from MWH. During the February 24, 2012 groundwater sampling event, all site monitoring wells, MW-1 through MW-7, and the drinking water well located cross-gradient from the site at OK Beauty Salon were sampled. DRO was detected at 2.37 mg/L above the groundwater cleanup levels in MW-2, and DRO was detected at concentrations below the groundwater cleanup levels in MW-1, MW-3, MW-4, and MW-6. Benzene, Toluene, Ethylbenzene, Xylenes and GRO were detected at concentrations below the groundwater cleanup levels in MW-2. The drinking water well at OK Beauty Salon did not detect any analytes in the drinking water sample collected on October 11, 2011.

Alyce Hughey

4/27/2012

Exposure Tracking Model Ranking

A new updated ranking with ETM has been completed for source area 77811 Former USTs.

Paul Horwath

4/27/2012

Exposure Tracking Model Ranking

Initial ranking with ETM completed for source area id: 77811 name: Former USTs

Paul Horwath

5/3/2012

Cleanup Complete Determination Issued

Following the completion of remedial action performed at this site from 1996 to 2011, residual soil contamination remains in the subsurface soil exceeding the ADEC’s Method Two ‘Migration to Groundwater’ soil cleanup levels in the area along the northern and western property boundaries along West Fireweed Land and Spenard Road. Residual groundwater contamination remains on site exceeding the ADEC’s Table C Groundwater Cleanup Levels. The affected groundwater is not currently used as a drinking water source, and the site is serviced by the City of Anchorage public water and sewer systems. The most current soil sample analytical data reported BTEX, GRO, and DRO contamination exceeding the applicable soil cleanup levels, along the northern and western property boundary, along West Fireweed Lane and Spenard Road. Any proposal to excavate, transport, move, treat, and/or dispose of residual contaminated soil at this “site” requires prior ADEC approval. Municipal public water service is currently provided to this property. Water wells may not be installed on this property without the prior notification, and approval, of ADEC. All groundwater monitoring wells, treatment wells, and subsurface treatment piping associated with this project must be properly decommissioned in accordance with ADEC’s November 2011 Monitoring Well Guidance. Decommissioning work should be completed when frost is not present in the soil. The decommissioning of these wells and any subsurface treatment piping should occur before August 30, 2012, and must be documented in a written report submitted to ADEC by November 30, 2012.

Paul Horwath

5/3/2012

Long Term Monitoring Complete

Administrative action on 5/1/2013.

Kristin Thompson

6/6/2012

Meeting or Teleconference Held

Staff attended the mid-year planning meeting at the ADEC office in Soldotna to discuss the decommissioning of monitoring wells and the recording of the Notice of Environmental Contamination for the site.

Alyce Hughey

7/17/2012

Document, Report, or Work plan Review - other

Reviewed the Decommissioning Work Plan for 2012, dated July 12, 2012, prepared by MWH, and issued a conditional approval to decommission MW-4, MW-5, MW-6, MW-7, SVE/MW-1, SVE/MW-2, SVE/MW-3 and AS-1. Conditions include 1) Our understanding and interpretation of this work plan is that a bentonite grout slurry will be used to fill the voids left during removal of the MW casings, and to pressure grout any piping associated with SVE/AS wells and subsurface delivery piping to be left in the subsurface. The use of bentonite chips or non-grout should only be substituted with our prior approval. There are drilling contractors preferring to use dry bentonite chips or pellets, but the drilling contractor shall not be allowed to take control of this field work and substitute dry/solid bentonite chips or pellets without prior ADEC approval. 2) Following the completion of this work, a written report documenting the implementation and completion of these approved work tasks shall be prepared and provided to our office, complete with the signature of the “qualified person” responsible for observing and documenting the field work.

Paul Horwath

11/14/2012

Meeting or Teleconference Held

Paul Horwath and Alyce Hughey attended annual planning meeting at MWH office in Anchorage to discuss the decommissioning activities conducted at the site in 2012.

Alyce Hughey

1/2/2013

Document, Report, or Work plan Review - other

Reviewed the August 2012 Monitoring Wells/Remediation System Decommissioning Report, dated November 6, 2012, from MWH. On August 22, 2012 four groundwater monitoring wells (MW-4, MW-5, MW-6 and MW-7), one air sparge well (AS-1), and three combination soil vapor extraction/monitoring wells (SVE/MW-1, SVE/MW-2 and SVE/MW-3) were decommissioned in accordance to the approved July 12, 2012 Decommissioning Work Plan for 2012 Former Tesoro 2 Go Mart #9 and ADEC’s July 17, 2012 e-mail correspondence with conditions.

Alyce Hughey

Contaminant Information

Name	Level Description	Media
DRO	Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation	Soil
GRO	Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation	Soil
DRO	> Table C	SoilGroundwater
BTEX	Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation	Soil

Name

Level Description

Media

Comments

DRO

Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation

Soil

GRO

Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation

Soil

DRO

> Table C

SoilGroundwater

BTEX

Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation

Soil

Control Type

Type	Details
No ICs Required

Type

Details

No ICs Required

Requirements

Description	Details
Advance approval required to transport soil or groundwater off-site.

Description

Details

Advance approval required to transport soil or groundwater off-site.

Corrective Action Complete Determination Tesoro Northstore 9 May 3 2012

No associated sites were found.

Missing Location Data

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Alaska Department of Environmental Conservation

Site Report: Tesoro - Northstore #9

Site Chronology

IC / Closure Details

Documents

Associated Sites

Problems/Comments

Action Information

Contaminant Information

Control Type

Requirements

Corrective Action Complete Determination Tesoro Northstore 9 May 3 2012

Missing Location Data

State of Alaska Department of Environmental Conservation